OS/2 guest random system crashes with Trap 8

After upgrading my host to Ubuntu Lucid I started getting random Trap 8 crashes (see screen shot) randomly. I had never seen this before I upgraded the host which has been running a number of earlier Ubuntu versions (Hardy onwards).

I first saw the problem using VirtualBox 3.1.6 but it also happens on 3.1.8 and 3.2.0.